1. Field of the Invention
The present invention relates to photoconductors and, more particularly, to near-room temperature operation polycrystalline infrared responsive photodetectors.
2. Brief Description of Prior Developments
Near-room temperature operation polycrystalline infrared responsive photodetectors such as the lead salts exhibit enhanced carrier lifetime due to majority carrier exclusion near the detector surface. This phenomenon limits responsivity to photons that are absorbed within a minority carrier diffusion length of this exclusion region and therefore skew the spectral response to shorter wavelengths due to the decrease in absorption coefficient as the photon energy approaches the band edge. In a thin film PbSe photoconductor, this limited responsivity can restrict the cutoff wavelength to shorter wavelengths and results in a lower internal quantum efficiency.
A need, therefore, exists for a way to increase internal quantum efficiency and to increase surface area for longer wavelength photons.